US7112024B2 - Self-attaching nut - Google Patents

Abstract

A self-attaching nut having a central pilot projecting from an end face of the body portion, an annular groove surrounding the pilot and an annular panel support face surrounding the groove, wherein the outer side wall includes a plurality of circumferentially spaced notches, each having an outer wall which extends from the bottom wall of the annular groove to the panel support face and the bottom wall of the groove includes a plurality of circumferentially spaced radial ribs integral with either the outer or inner side walls of the annular groove having a radial end spaced from the opposed side wall and a top face inclined toward the bottom wall of the annular groove providing improved torque resistance and push-off strength. Alternating circumferentially overlapping radial ribs integral with the pilot and the outer groove wall and ribs which extend below the bottom wall of the groove are also disclosed.

Description

RELATED APPLICATIONS

This application is a divisional application of U.S. Ser. No. 10/439,562, filed May 16, 2003 now U.S. Pat. No. 6,862,927, which is application is a continuation-in-part application of U.S. Ser. No. 10/232,335, filed Aug. 30, 2002, now U.S. Pat. No. 6,851,904.

FIELD OF THE INVENTION

This invention relates to self-attaching female fasteners, particularly including pierce and clinch nuts, which may be formed by conventional cold header techniques including secondary operations and which provide improved retention and resistance to rotation of the fastener on a panel following installation.

BACKGROUND OF THE INVENTION

Self-attaching female fasteners, including pierce and clinch nuts, formed by cold header techniques and secondary press operations generally include a body portion having an end face, a central pilot portion projecting from the end face of the body portion having a bore through the central pilot portion, an annular groove in the end face of the body portion surrounding the pilot portion and an annular panel support face or flange portion surrounding the annular groove. Generally, at least one of the inner and outer side walls of the annular groove are inclined toward the other side wall to provide a restricted opening to the annular groove adjacent the annular panel support face to improve retention of the fastener following installation. Further improved retention of the fastener on a panel is provided by inclining both the inner and outer side walls of the annular groove toward the opposing side wall forming a “dovetail” shaped re-entrant groove. When the panel is deformed against the bottom wall of the groove by a die member or die button having a projecting annular lip configured to be received in the annular groove, the panel is simultaneously deformed beneath the undercuts provided by the dovetail shaped re-entrant groove. Alternatively, the outer side wall of the annular groove may be inclined toward the pilot portion and the pilot portion may be deformed radially outwardly during installation as disclosed, for example, in U.S. Pat. No. 6,276,040 to form a secure installation having sufficient push-off strength. However, most installations of self-attaching nuts also require sufficient torque resistance or anti-rotation means preventing rotation of the self-attaching fastener on the panel following installation, particularly where the nut and panel assembly is attached to a second component by a bolt or other male threaded member using a torque wrench or the like.

The prior art discloses various anti-rotation or torque resistant means for self-attaching female fasteners of this type. For example, U.S. Pat. No. 5,531,552, assigned to the predecessor in interest of this application, discloses forming a plurality of circumferentially spaced protrusions having radial channels therebetween in the bottom wall of the groove which provides improved torque resistance. U.S. Pat. No. 5,549,430, also assigned to the predecessor in interest of the assignee of this application, discloses a self-attaching nut of this type, wherein the bottom wall of the groove includes a plurality of spaced arcuate or semi-circular protrusions integral with the pilot portion which provide improved torque resistance, but which also deforms panel metal beneath the inclined outer side wall of the annular groove, also providing improved push-off strength following installation. U.S. Pat. No. 5,782,594 discloses a pierce nut having a central recess, rather than a groove having an inner side wall and a plurality of circumferentially spaced radial notches or pockets formed in the panel support face which, when formed by a die member, forms radially inwardly projecting bead-like projections in the side wall of the recess, providing improved torque resistance. The above-referenced U.S. Pat. No. 6,276,040, also discloses opposed V-shaped webs integral with the bottom wall of a dovetail shaped annular groove and the opposed inner and outer side walls of the annular groove. Further, the prior art includes pierce nuts of this type having rectangular radial ribs or lugs which bridge the bottom wall of the annular groove and are integral with both the inner and outer side walls of the groove. However, where the ribs are integral with both the inner and outer side walls of the annular groove, deformation of a panel against the ribs may cause deformation or distortion of the thread cylinder unless the pilot is reinforced.

However, many applications of self-attaching nuts of this type formed by cold heading require further improved integrity of the nut and panel assembly, including improved torsion resistance and push-off strength. The embodiments of the improved self-attaching nut of this invention provides improved integrity of the nut and panel assembly, including improved torsion resistance and push-off strength.

SUMMARY OF THE INVENTION

The self-attaching nut or female fastener element of this invention may be formed by conventional cold header techniques and may be utilized as a pierce or clinch nut to provide superior integrity in a fastener and panel assembly, including improved torsion resistance and push-off strength. As used herein, the term “self-attaching nut,” includes both pierce and clinch nuts. During installation of a pierce nut, the central pilot portion pierces or punches an opening in the panel and the panel is then deformed into the annular groove by a die member or die button. A clinch nut is installed in a preformed panel opening, but a pierce nut may also be utilized as a clinch nut. The self-attaching nut of this invention includes a body portion having an end face, a central pilot portion projecting from the end face having a bore therethrough, an annular groove in the end face surrounding the pilot and an annular panel support face or flange portion surrounding the annular groove. The annular groove includes an inner side wall adjacent the pilot portion, a bottom wall and an outer side wall extending from the bottom wall to the panel support face. In the preferred embodiments of the self-attaching nut of this invention, at least one of the inner and outer side walls of the annular groove is inclined toward the other side wall forming a restricted opening to the annular groove. In a preferred embodiment of the self-attaching nut of this invention, the outer side wall of the annular groove is inclined toward the pilot portion and in the most preferred embodiment, both side walls of the groove are inclined to the other side wall, forming a dovetail-shaped re-entrant groove, wherein the outer side wall is inclined toward the pilot portion and the inner side wall is inclined toward the outer side wall providing improved push-off strength. However, as set forth above, the prior art includes self-attaching nuts having the features thus far described.

As set forth below, this application discloses several embodiments of the self-attaching nut of this invention having improved torque resistance. The improvements described below may be utilized in various combinations to provide improved torque resistance and push-off strength depending upon the application.

One feature of the self-attaching nut of this invention is that the outer side wall of the annular groove includes a plurality of circumferentially spaced radial notches each having an outer side wall and opposed generally radial walls. In a preferred embodiment, the notches extend from the bottom wall of the annular groove to the annular panel support face. During installation of the self-attaching nut to a panel, the panel is deformed radially into the radial notches providing improved torque resistance. In a preferred embodiment, wherein the outer side wall of the annular groove is inclined radially inwardly toward the pilot portion, the outer wall of the notches may extend generally or substantially perpendicular to the annular support face of the self-attaching nut.

Further improvement in torque resistance may be provided by radial ribs projecting from the bottom wall of the annular groove each having a top face spaced from the bottom wall. In one preferred embodiment, the radial ribs are integral with the outer side wall of the annular groove at or above a midportion of the outer side wall and the top face of the ribs is inclined from the outer side wall toward the bottom wall of the annular groove but spaced from the inclined inner side wall of the annular groove, thereby providing improved torque resistance, but also deforming the panel beneath the inclined inner side wall and providing improved push-off strength. In one preferred embodiment, the radial inner ends of the radial ribs merge with the bottom wall flush with the bottom wall. In another preferred embodiment, the radial ribs continue “beneath” the bottom wall of the bottom wall in radial channels, such that the top face of the radial ribs extends below the plane of the bottom wall providing further improved torque resistance.

In the disclosed embodiments, the radial ribs may be generally rectangular in cross-section having a planar top face, but preferably include outwardly inclined side faces which direct panel metal into the bottom wall of the groove. In one preferred embodiment, the radial ribs are integral with the inwardly inclined outer side wall of the annular groove and spaced between the radial notches. In another preferred embodiment, the radial ribs are integral with the outer wall of the radial notches, but preferably have a width measured circumferentially less than the circumferential width of the radial notches, such that panel metal will flow around the radial ribs into the radial notches. As used herein, the phrase “integral with the outer side wall” of the annular groove includes radial ribs integral with either the inclined outer side wall of the annular groove, when used, or the outer wall of the radial notches, because the outer wall of the radial notches, when used, further define the outer side wall of the annular groove. In another preferred embodiment, the radial ribs are integral with the inner side wall of the annular groove, are inclined toward the bottom wall and spaced from the outer wall as described above with regard to the preferred embodiments wherein the radial ribs are integral with the outer side wall. In this embodiment, the top face of the radial ribs may extend radially beneath the plane of the bottom wall of the annular groove in a radial channel, as described above.

Further improvement in torque resistance may be provided by cooperation of the radial ribs. In one preferred embodiment, a pair of radial ribs is provided in a plurality of the radial notches integral with the outer wall of the radial notches, wherein the opposed radial ribs each include a top face which may extend to the panel support face surrounding the annular groove, opposed outwardly inclined faces, which are angled toward the opposed face of the adjacent radial rib, directing panel metal between the ribs and preferably including inwardly inclined faces forming an undercut between the pair of ribs providing further improved push-off strength and torque resistance. In another embodiment, the circumferentially spaced radial ribs comprise alternating radial ribs integral with the inner side wall or pilot portion and the outer side wall, wherein the radial ribs have a radial length greater than one-half the radial width of the bottom wall of the annular groove, such that the ribs overlap circumferentially providing further improved torque resistance. In this embodiment, the radial ribs are inclined toward the bottom wall, but spaced from the opposed wall, such that, during installation, panel metal is deformed radially outwardly by the ribs integral with the inner wall of the annular groove beneath the inclined outer wall and radially inwardly beneath the inclined inner side wall by the radial ribs integral with the outer side wall.

Further improved push-off strength is provided by radial ribs integral with either the inner or outer side wall of the annular groove having an end portion spaced from the other side wall above the plane of the bottom wall and an inwardly inclined end face integral with the bottom wall forming an undercut and entrapping panel metal during installation. As will be understood from the above description, in the preferred embodiments of the self-attaching nut of this invention, the radial ribs are integral with one of the inner and outer side walls of the annular groove each having an end portion spaced from the opposed side wall and the radial ribs preferably include a top face which is angled toward the bottom wall. However, a similar effect may be provided by a radial rib integral with either the inner or outer side wall, angled toward the bottom wall, wherein the radial end portion is adjacent the opposed inner or outer side wall and including a circumferential channel.

As will be understood from the above summary of the invention, several embodiments of the self-attaching nut of this invention are disclosed herein which include improved integrity when installed in a panel, including push-off strength and torque resistance. Further advantages and meritorious features of the self-attaching nut of this invention will be more fully understood from the following description of the preferred embodiments, the appended claims and the drawings, a brief description of which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of one embodiment of the self-attaching nut of this invention;

FIG. 2 is a top view of the self-attaching nut shown inFIG. 1;

FIG. 3 is a side cross-sectional view ofFIG. 2 in the direction ofview arrows3—3;

FIG. 3A is an enlarged cross-sectional view of the annular groove in the embodiment of the self-attaching nut shown inFIGS. 1 to 3;

FIG. 4 is an enlarged cross-sectional view ofFIG. 3 in the area ofview circle4;

FIG. 5 is a partial cross-sectional view ofFIG. 4 in the direction ofview arrows5—5;

FIG. 6 is a top perspective view of an alternative embodiment of the self-attaching nut of this invention;

FIG. 7 is a top view of the self-attaching nut shown inFIG. 6;

FIG. 8 is a partial side cross-sectional view ofFIG. 7 in the direction of view arrows8—8;

FIG. 9 is a partial cross-sectional view ofFIG. 8 in the direction ofview arrows9—9;

FIG. 10 is a partial cross-sectional view ofFIG. 8 in the direction ofview arrows10—10;

FIG. 11 is a top perspective view of a further alternative embodiment of the self-attaching nut of this invention;

FIG. 12 is a top view of the self-attaching nut shown inFIG. 11;

FIG. 13 is a partial side cross-sectional view ofFIG. 12 in the direction ofview arrows13—13;

FIG. 14 is a partial cross-sectional view ofFIG. 13 in the direction ofview arrows14—14;

FIG. 15 is a partial cross-sectional view ofFIG. 13 in the direction ofview arrows15—15;

FIG. 16 is a top perspective view of a further alternative embodiment of the self-attaching nut of this invention;

FIG. 17 is a partial side cross-sectional view ofFIG. 16 in the direction ofview arrows17—17;

FIG. 18 is a top perspective view of a further alternative embodiment of this invention;

FIG. 19 is a partial top view of the embodiment of the self-attaching nut shown inFIG. 18;

FIG. 20 is a partial cross-sectional view ofFIG. 19 in the direction ofview arrows20—20;

FIG. 21 is a top perspective view of a further alternative embodiment of the self-attaching nut of this invention;

FIG. 22 is a partial top view of the self-attaching nut shown inFIG. 21;

FIG. 23 is a partial cross-sectional view ofFIG. 22 in the direction ofview arrows23—23;

FIG. 24 is a partial cross-sectional view ofFIG. 23 in the direction ofview arrows24—24;

FIG. 25 is a top perspective view of a further alternative embodiment of the self-attaching nut of this invention;

FIG. 26 is a partial top view of the self-attaching nut shown inFIG. 25; and

FIG. 27 is a partial cross-sectional view ofFIG. 26 in the direction ofview arrows27—27.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As will be understood, the following description of the preferred embodiments and the appended drawings are for illustration purposes only and do not limit the scope of this invention except as set forth in the following claims.FIGS. 1 to 5 illustrate a first embodiment of the self-attachingnut20 of this invention including abody portion22 having an end face24 (seeFIG. 1), acentral pilot portion26, anannular groove28 surrounding thepilot portion26 and an annularpanel support face30 surrounding theannular groove28. Thepilot portion26 includes an annular preferablyplanar end face32 and abore34 through the pilot portion. Where the self-attachingnut20 of this invention is utilized as a pierce nut, theend face32 is preferably above the plane of the annularpanel support face30, as best shown inFIG. 3, such that thepilot portion26 pierces an opening in a metal panel as is well known in this art. As best shown inFIG. 3A, theannular groove28 includes aninner side wall36 which, in the disclosed embodiment, is also the outer side wall of thepilot portion26, abottom wall38 and anouter side wall40. As set forth above, in the preferred embodiments of the self-attaching nuts of this invention, at least one of the inner andouter side walls36 and40, respectively, is inclined toward the opposed side wall forming a restricted opening to theannular groove28. In a preferred embodiment of this invention, theouter side wall40 is inclined toward thepilot portion26 or more specifically toward theinner side wall36 and in the most preferred embodiment, the inner andouter side walls36 and40 are inclined toward each other as shown inFIG. 3A, forming a dovetail-shaped re-entrant groove providing improved push-off strength when the self-attaching nut is installed in a panel (not shown). Thebore34 may be threaded as shown or thebore34 may be cylindrical for receipt of a thread forming or thread rolling male fastener, such as a screw or bolt. Thebody portion22 may be polygonal as shown having a plurality offlat faces42 or the outer surface of the self-attaching nut may also be cylindrical. As thus far described, the self-attaching nut of this invention is generally conventional, although several of the prior art references do not include both an inner and outerinclined side wall36 and40, respectively, which results in reduced push-off strength.

As set forth above, the self-attaching nut of this invention provides improved integrity of the nut and panel assembly, including improved torque resistance and push-off strength. One important feature of the self-attaching nut shown inFIGS. 1 to 5 is the circumferentially spacedradial notches44 each having anouter wall46 and opposed generallyradial walls48. Theradial walls48 may also be inclined inwardly toward each other from the outer wall46 (not shown) to provide further torque resistance. As best shown inFIG. 3, theouter wall48 of the radial notches extends generally perpendicular to the panelplanar support face30 in the disclosed embodiment. Further, in a preferred embodiment, theradial notches44 extend from thebottom wall38 of theannular groove28 to the top annularpanel support face30. As will be understood, during installation of the self-attachingnut20, a panel (not shown) will be deformed into theradial notches44 providing substantially improved torque resistance. In the disclosed embodiment, the self-attachingnut20 includes eightradial notches44 and the body portion includes eightflats42, wherein theradial notches44 are defined in the corner portions50 (seeFIG. 1), providing maximum torque resistance.

Although theradial notches44 may be used alone to provide torque resistance, the embodiment of the self-attachingnut20 illustrated inFIGS. 1 to 5 further includes a plurality ofradial ribs52. In this embodiment of the self-attachingnut20 of this invention, theradial ribs52 are integral with the inclinedouter side wall40 of theannular groove28. Each of theradial ribs52 include atop face54 which is inclined from theouter side wall40 of theannular groove28 toward thebottom wall38. In the disclosed embodiment of the self-attachingnut20, the radial inner ends56 of theradial ribs52 merge with thebottom wall38 as best shown inFIG. 4 and the radial inner ends56 of theribs52 are spaced from theinner side wall36 of theannular groove28 as best shown inFIGS. 1 and 2. In the disclosed embodiment, thetop face54 of theradial ribs52 is generally rectangular; however, the side faces58 of the radial ribs are preferably angled outwardly as best shown inFIG. 5. The outwardly inclined faces58 direct panel metal toward thebottom wall38 of theannular groove28, improving filling of theannular groove28 with panel metal during installation. Further, the inclined top faces54 of theradial ribs52 direct panel metal radially inwardly beneath the inclinedinner side wall36 as the panel metal is deformed against theradial ribs52, providing further improved torsion resistance and push-off strength.

As will be understood by those skilled in this art and described further in the above-referenced U.S. patents, the self-attachingnut20 illustrated inFIGS. 1 to 5 may be utilized as a pierce nut, wherein the planar annular end face32 of thecentral pilot portion26 is driven against a panel (not shown) which is supported on a die button (not shown) and the pilot portion then pierces an opening in the panel which receives thepilot portion26 therethrough. The die button will include an annular lip configured to be received within theannular groove28 which deforms the panel surrounding the panel opening into theannular groove28 and against thebottom wall38 and the top faces54 of theradial ribs52. The inclinedtop face54 of the radial ribs then directs panel metal beneath the inclinedinner side wall36, providing improved retention and the panel metal is further deformed around the inclined side faces58 of the radial ribs and into theradial notches44 providing further improved torque resistance. In a preferred embodiment, the inclinedtop face54 is spaced below the annularpanel support face30 and integral with the inclinedouter side wall40 at or above the midportion60 (i.e., about one half the distance between thebottom wall38 and the panel support face30) of the inclinedouter side wall40 as shown inFIG. 4, providing optimum torque resistance. As will now be understood, theradial notches44 in combination with theradial ribs52 provide superior torque resistance and further improve the push-off strength or integrity of the nut and panel installation.

FIGS. 6 to 10 illustrate a second embodiment of a self-attachingnut120 of this invention, wherein the common elements of the self-attachingnut120 are numbered the same as the elements of the self-attachingnut20 described above except that the elements of the self-attachingnut120 are numbered in the 100 series to simplify the description of the self-attachingnut120. That is, the self-attachingnut120 shown inFIGS. 5 to 10 include abody portion122 having anend face124, acentral pilot portion126, anannular groove128 surrounding the pilot portion and an annularpanel support face130 surrounding theannular groove128. In this embodiment of the self-attachingnut120, theradial ribs152 are integral with the inclinedouter side wall140, generally equally spaced between theradial notches144, as described above in regard to the self-attachingnut20 shown inFIGS. 1 to 5. However, thetop face154 of the radial ribs extends below the plane of thebottom wall138 of theannular groove128, as best shown inFIG. 8, wherein the radialinner end portion156 of each of theradial ribs152 is received in aradial channel162 as shown inFIGS. 8 and 10. The radialinner end156 of theradial ribs152 is, however, spaced from theinner side wall136 of the annular groove in that it is not integral with the outer wall of the pilot portion or the inclinedinner wall136 of the annular groove. All other features of the self-attachingnut120 may be identical to the self-attachingnut20 described above with regard toFIGS. 1 to 5.

The second embodiment of the self-attachingnut120 shown inFIGS. 6 to 10 has further advantages over the self-attachingnut20 shown inFIGS. 1 to 5. First, during installation of the self-attachingnut120 in a panel (not shown), the panel metal will be driven against the inclinedtop face154 into theradial channels162 in thebottom wall138 of theannular groove128, providing further improved torque resistance. Further, the panel will be driven beneath the inclinedinner side wall136 by the inclined radialtop face154 which extends to adjacent the inclinedinner side wall136, providing further improved push-off strength. The remaining features of the second embodiment of the self-attaching nut shown inFIGS. 6 to 10 may be identical to the self-attachingnut20 described in more detail above, and therefore no further description of the second embodiment is necessary for a full understanding of this embodiment.

The third embodiment of the self-attachingnut220 shown inFIGS. 11 to 15 is essentially identical to the second embodiment shown inFIGS. 6 to 10, except that theradial ribs252 are integral with theinner side wall236 of theannular groove228 which, in the disclosed embodiment, is also the external surface of thecentral pilot portion226. That is, the self-attachingnut220 includes acentral pilot portion226, anannular groove228 surrounding the pilot portion and an annularpanel support face230 surrounding theannular groove228. Except as described above, the self-attachingnut220 is identical to the self-attachingnut120 described above and the elements of the self-attachingnut220 are numbered the same as the elements of the self-attachingnut120 except that the reference numbers of this third embodiment are numbered in the 200 series.

In this third embodiment of the self-attachingnut220, panel metal is driven against thebottom wall238 of theannular groove228 and the outwardly inclined top faces254 of theradial ribs252 during installation of the self-attaching nut in a panel (not shown). The panel metal is thus driven beneath the inclinedouter side wall240 and into theradial channels262 by the inclined top faces254, providing a very secure installation with improved torque resistance as described above with regard to the self-attachingnut120. Further, as described above with regard to the self-attachingnut20, the panel metal is simultaneously driven into theradial notches244 in theouter side wall240. Further, in this third embodiment, there is less likelihood of distortion of the threadedbore234 because theradial ribs252 do not drive panel metal toward thepilot portion226. As set forth above, all other elements or features of the self-attachingnut220 may be identical to the self-attachingnuts20 and120 described above and therefore, no further description of this embodiment is required for a full understanding of this embodiment.

The fourth embodiment of the self-attachingnut320 shown inFIGS. 16 and 17 differs from the embodiment of the self-attachingnut20 shown inFIGS. 1 to 5 in two material respects. First, thebottom wall338 of theannular groove328 includes a plurality of alternating circumferentially spacedribs352 and353, including a first plurality of circumferentially spacedradial ribs352 integral with the outer side wall of theannular groove328 and a second plurality ofradial ribs353 integral with theinner side wall336 of theannular groove328. In a preferred embodiment of the self-attachingnut320, the radial ends356 of theradial ribs352 and353 extend beyond amidportion364 of theannular groove328, such that the alternatingradial ribs352 and353 circumferentially “overlap.” That is, the radial inner ends356 of theradial ribs352 extend beyond the radial inner ends356 of theradial ribs353 in thebottom wall338 of theannular groove328, such that theradial ribs352 and353 circumferentially overlap, as best shown inFIG. 16. This alternately overlappingradial ribs352 and353 provide superior torque resistance. Further, upon installation of the self-attachingnut320 in a panel, the top faces354 of theradial ribs352 and353 direct panel metal beneath both the inclinedinner side wall336 and the inclinedouter side wall340 providing improved push-off strength.

The second difference of the self-attachingnut320 shown inFIGS. 16 and 17 is that theradial ribs352 are integral with theouter wall346 of theradial notches344, but have a circumferential width less than the circumferential width of the radial notches measured between the opposed radial walls348. As described above with regard to the embodiment of the self-attachingnut20 shown inFIGS. 1 to 5, the side faces358 of theradial ribs352 and353 are inclined outwardly from thetop face354 which, during installation of the self-attachingnut320 in a panel (not shown), directs panel metal between theradial ribs352 and the opposed radial walls348. In a preferred embodiment of the self-attachingnut320, the radial outer end of theradial notches352 is spaced below the plane of the annularpanel support face330 at or above a midportion of theouter walls346, such that the panel metal will fill the upper portion of theradial notches344.

The self-attachingnut320 shown inFIGS. 16 and 17 provide further advantages over the self-attaching nuts previously described. First, the alternating overlappingradial ribs352 and353 provide superior torque resistance over the previously described embodiments. Second, because the inclined top faces358 of theradial ribs352 and353 alternate radially inwardly and outwardly toward the inner andouter side walls336 and340, respectively, more panel metal is driven beneath the inclined inner andouter side walls336 and340, providing improved push-off strength and balancing the forces resulting from the panel being driven against the radial ribs. Finally, forming theradial ribs352 integral with theouter wall346 of theradial notches344 locates the radial ribs further from the axis of thebore334, providing further torque resistance.

As set forth above, the self-attachingnut320 shown inFIGS. 16 and 17 may otherwise be identical to the self-attachingnut20 described above with regard toFIGS. 1 to 5 and have been numbered the same, except that the elements are numbered in the 300 series and therefore no further description is required for a complete understanding of this embodiment of the self-attaching nut of this invention.

The fifth embodiment of the self-attachingnut420 of this invention shown inFIGS. 18 to 20 differs from the embodiment of the self-attachingnut20 shown inFIGS. 1 to 5 in two material respects. As set forth above in the Background of the Invention, it is not desirable to utilize radial ribs which bridge the inner and outer side walls of the annular groove to avoid thread distortion. In the second preferred embodiments of the self-attaching nuts of this invention, the radial ribs are integral with either the inner or outer side walls of the annular groove, but spaced from the opposed wall, particularly where the radial ribs are integral with the outer side wall as described above with regard to the embodiments of the self-attachingnuts20,120,220 and320 described above. In the embodiment of the self-attachingnut120 shown inFIGS. 6 to 10, theradial ribs152 extend below the plane of thebottom wall138 and are therefore not integral with the outer side wall of thepilot portion126, further reducing the likelihood of thread distortion. In this fifth embodiment of the self-attachingnut420, theradial ribs452 extend to adjacent theinner side wall436 of theannular groove428 above the plane of thebottom wall438 as best shown inFIG. 20. However, theradial ribs452 further includecircumferential channels464 having opposed faces466 which, in the disclosed embodiment, extend to thebottom wall438 of theannular groove428 as best shown inFIG. 20. Thus, the inwardly directed force during installation of this embodiment of the self-attachingnut420 in a panel (not shown), the inward force of a panel against the top faces254 is reduced, reducing the likelihood of distortion of the threads of thebore434. It is also believed that this embodiment of the self-attachingnut420 may provide further torque resistance because of the increased area of the side faces458 of theradial ribs452. The remaining features or elements of the self-attachingnut420 shown inFIGS. 18 to 20 may be identical to the embodiment of the self-attachingnut20 shown inFIGS. 1 to 5 and have therefore been numbered the same as the self-attachingnut20 except that the self-attachingnut420 is numbered in the 400 series. Therefore, no further description of the embodiment of the self-attachingnut420 is necessary for a complete understanding of this embodiment.

The sixth embodiment of the self-attachingnut520 shown inFIGS. 21 to 24 differs from the embodiments of the self-attaching nuts previously described in that a plurality of the circumferentially spacedradial notches544 include a pair of circumferentially spacedradial ribs552 and553 integral with theouter wall546 and one of the opposedradial walls548 of theradial notches544, as shown. In this embodiment, theradial ribs552 and553 each include atop face554 which may extend to thepanel support face530 as shown inFIGS. 23 and 24 or spaced below thepanel support face530 as described above with the previous embodiments. Theradial ribs552 and553 further include opposed outwardlyinclined faces568 and opposed inwardly inclined faces570, wherein the inwardly inclined faces570 form an undercut as shown inFIG. 24. Thus, during installation of the self-attachingnut520 in a panel (not shown), the panel metal is deformed against the opposed outwardlyinclined faces568 and beneath the opposed inwardly inclined faces570 against thebottom wall538 of the annular groove. Further, the radial inner ends556 of theradial ribs552 and554 are spaced above the plane of thebottom wall538 of theannular groove528 and include an inwardlyinclined end face572 as shown inFIG. 23. As shown inFIGS. 21 and 22, theradial ribs552 and553 are located in alternativeradial notches544. That is, four of theradial notches544 include a pair ofradial ribs552 and553 and the remaining four radial notches are clear or open as described above with regard toFIG. 1.

The sixth embodiment of the self-attachingnut520 shown inFIGS. 21 to 24 and described above provides further advantages over the embodiments previously described. As will be understood by those skilled in this art, a die member (not shown) utilized to install the self-attachingnut520 will include an annular lip portion as utilized for installing self-attaching nuts of this type and shown in the above-referenced patents. However, the annular lip may further include radial portions for receipt between each pair ofradial ribs552 and553. Thus, during installation, panel metal is deformed between theradial ribs552 and553 against the opposed outwardlyinclined faces568 and beneath the opposed inwardly inclined faces570, providing further improved torque retention and push-off strength. Further, as the panel metal is deformed against thebottom wall538 of theannular groove528, panel metal will be deformed beneath the inwardly inclined end faces572 of theradial ribs552 and553, providing further improved push-off strength. Finally, the increased area, of the side faces558 and the location of the radial ribs integral with theouter wall546, provides further improved torque resistance. This increased torque resistance reduces the required number of radial ribs. All other elements or features of the self-attachingnut520 may be identical to the self-attaching nuts previously described and the reference numbers are identical to the previously described self-attaching nuts, except that the reference numbers are in the 500 series. That is, the self-attachingnut520 includes acentral pilot portion526 having abore534 therethrough, anannular groove528 surrounding thepilot portion526 and an annularpanel support face530 surrounding theannular groove528.

Finally, the seventh embodiment of the self-attachingnut620 shown inFIGS. 25 to 27 differs from the embodiment of the self-attachingnut520 shown inFIGS. 21 to 24 in that each of theradial notches644 includes only oneradial rib652 integral with theouter wall646 of theradial notches644, generally equally spaced between theradial walls648. That is, in the embodiment of the self-attachingnut620 shown inFIGS. 25 to 27, each of theradial notches644 includes aradial rib652 integral with theouter wall646 of the radial notches having a circumferential width less than the circumferential width of theradial notches644 measured between the opposedradial walls648, wherein theradial ribs652 extend to thepanel support face630 as shown inFIG. 27 and the radial inner ends656 of theradial ribs652 is spaced above the plane of thebottom wall638 of theannular groove628 and theradial ribs652 each include inwardly inclined end faces672 as shown inFIG. 27. As will be understood, however, theradial ribs652 may also have a width equal to the width of thenotches644. Except as described above, the self-attachingnut620 may be identical to the embodiment of the self-attachingnut520 and the previously described embodiments and therefore the self-attachingnut620 is numbered the same, except that the reference numbers are in the 600 series.

During installation of the seventh embodiment of the self-attachingnut620 shown inFIGS. 25 to 27 in a panel (not shown), panel metal is deformed against thebottom wall638 and the inwardly inclined top faces654 of theradial ribs652. The top faces654 of theradial ribs652 then deform the panel metal radially inwardly beneath the inclinedinner side wall636 and beneath the inwardly inclined end faces672 providing improved push-off strength. The panel metal is further deformed circumferentially against the inclined side faces658 into theradial notches644 and against the side faces658 to thebottom wall638 of theannular groove628. Because the side faces658 of theradial ribs652 have a greater surface area, theradial ribs652 provide greater torque resistance than where the radial ribs extend to a midportion of the outer wall.

As will now be understood from the above description of the embodiments of the self-attaching nut of this invention, the improvements in torque resistance and push-off strength provided by the various embodiments of the self-attaching nuts disclosed herein may be utilized individually or in combination to provide improved torque resistance and push-off strength. In the preferred embodiments, the radial ribs are integral with either the inner or outer side walls of the annular groove and the radial inner ends of the radial ribs are preferably spaced from the opposed side wall. In the more preferred embodiments, the radial ribs are integral with the outer wall of the annular groove, but may be integral with either the inclined outer side wall of the annular groove or the outer wall of the radial notches which, in a preferred embodiment, extends generally perpendicular to the panel support face surrounding the annular pilot. However, as set forth above, the outer wall of the radial notches, when utilized, forms the outer side wall of the annular groove and thus, as used herein, reference to the radial notches as integral with the outer side wall includes radial notches integral with the outer wall of the radial notches. In a preferred embodiment, the outer side wall of the annular groove is inclined toward the pilot portion and the inner side wall of the annular groove is inclined toward the outer side wall, forming a dovetail-shaped annular groove providing improved push-off strength. In the disclosed embodiments of the self-attaching nuts, the bottom wall of the annular groove extends generally perpendicular to the axis of the bore through the pilot portion. However, the bottom wall may also be inclined toward either the inner or outer side wall of the annular groove. Further, as will be understood by those skilled in this art, the bottom wall must be inclined toward either the inner or outer side wall of the annular groove a few degrees to permit removal of the self-attaching nut from a die member used to form the annular groove. This would be true of any self-attaching nut of this type.

As set forth above, the embodiments of the self-attaching nuts described above may be utilized as either a pierce or clinch nut. In either method of installation, the metal panel is supported in a die press on a die member or die button. The die button includes an annular clinching lip configured to be received in the annular groove generally having outwardly tapered surfaces as is known in this art. In a conventional application, the die button is located in the lower die shoe of a die press and the self-attaching nut is received in an installation head located in the upper die shoe having a reciprocating plunger which drives the self-attaching nut against the panel. Where the self-attaching nut is utilized as a pierce nut, the end face of the pilot portion pierces or punches an opening in the panel and the annular lip of the die button deforms the panel metal into the annular groove and against the bottom wall of the groove as is known in this art. Where the self-attaching nut is utilized as a clinch nut, an opening is preformed in the panel configured to receive the pilot portion therethrough and the annular lip of the die member then deforms the panel metal into the re-entrant groove and against the bottom wall in the same manner as described.

As will be understood by those skilled in this art, various modifications may be made to the embodiments of the self-attaching nut described above and shown in the attached drawings within the purview of the appended claims. For example, the features of the embodiments disclosed herein may be utilized alone or in combination as set forth above. More specifically, the radial notches may be utilized without the radial ribs and vice versa depending upon the requirements of the application. However, the preferred embodiments of the self-attaching nut includes radial notches in combination with one of the embodiments of the radial ribs disclosed herein. In the more preferred embodiments, the radial ribs are generally equally circumferentially spaced and integral with either the inner or outer side walls of the annular groove and spaced from the opposed side wall to reduce deformation of the thread cylinder of the bore through the pilot portion. Further, the bore may be unthreaded to receive a self-tapping or thread rolling male fastener. In the more preferred embodiments, the annular groove includes an inner wall inclined toward the outer wall of the annular groove and an outer wall inclined toward the pilot portion and the outer wall includes radial ribs integral with the outer wall of the annular groove, either integral with the inclined outer side wall or the outer wall of the radial notches. The outer wall of the radial notches may be perpendicular to the panel support face, as disclosed in the embodiments illustrated in the drawings, or the outer wall of the radial notches may be inclined, preferably toward the pilot portion. Alternatively, the radial ribs may be integral with the inner wall of the annular groove or the pilot portion or more preferably the self-attaching nut may include alternating circumferentially spaced radial ribs integral with the pilot portion and the outer wall of the annular groove as shown, for example, inFIGS. 16 and 17. Further, in the preferred embodiments, the bottom wall of the annular groove is generally perpendicular to the axis of the bore through the pilot portion or parallel to the panel support face. However, the bottom wall may also be angled inwardly toward the pilot portion. As will be understood by those skilled in this art, however, the bottom wall will generally be inclined toward the pilot portion about one to three degrees to permit removal of the self-attaching nut from the die member of the cold header following formation of the self-attaching nut of this invention. In the preferred embodiments of the self-attaching nut of this invention, the radial ribs are integral with either the inner or outer side walls of the annular groove at or above a midportion of the side wall. Having described several preferred embodiments of the self-attaching nut of this invention, the invention is now claimed as follows.

Claims (21)

1. A self-attaching nut for attachment to a panel, comprising: a body portion having an end face, a central pilot portion projecting from said end face of said body portion having a bore therethrough, an annular groove in said end face of said body portion surrounding said pilot portion and an annular panel support face surrounding said annular groove, said annular groove including an inner wall adjacent said pilot portion, a bottom wall and an outer side wall, and a plurality of circumferentially spaced generally radial ribs each having a planar top face, comprising a first plurality of circumferentially spaced ribs integral with said outer side wall extending beyond a midportion of said bottom wall and spaced from said inner side wall of said annular groove and a second plurality of circumferentially spaced ribs integral with said inner side wall extending beyond said midportion of said bottom wall and spaced from said outer side wall of said annular groove, such that said first and second plurality of circumferentially spaced ribs overlap at said midportion of said bottom wall.

2. The self-attaching nut as defined inclaim 1, wherein said outer side wall of said annular groove includes a plurality of circumferentially spaced radial notches.

3. The self-attaching nut as defined inclaim 2, wherein said radial notches each include an outer wall extending from said bottom wall of said annular groove to said annular panel support face and opposed generally radial walls.

4. The self-attaching nut as defined inclaim 3, wherein said first plurality of circumferentially spaced ribs integral with said outer side wall are integral with said outer wall of said radial notches.

5. The self-attaching nut as defined inclaim 1, wherein each of said radial ribs are inclined toward said bottom wall of said annular groove.

6. The self-attaching nut as defined inclaim 1, wherein said outer side wall of said annular groove is inclined toward said pilot portion.

7. The self-attaching nut as defined inclaim 1, wherein said planar top face of each of said first and second plurality of circumferentially spaced ribs is generally rectangular.

8. The self-attaching nut as defined inclaim 1, wherein said inner side wall of said annular groove is inclined toward said outer side wall and said outer side wall of said annular groove is inclined toward said inner side wall.

9. A self-attaching nut for attachment to a panel, comprising:

a body portion having an end face, a central pilot portion projecting from said end face of said body portion having a bore therethrough, an annular groove in said end face of said body portion surrounding said pilot portion and an annular panel support face surrounding said annular groove, said annular groove including an inner side wall adjacent said pilot portion, a bottom wall and an outer side wall, and a plurality of circumferentially spaced generally radial ribs each having a planar top face inclined toward said bottom wall of said annular groove, including a first plurality of circumferentially spaced ribs integral with said outer side wall at or above a midportion of said outer side wall and spaced from said inner side wall of said annular groove and a second plurality of circumferentially spaced ribs integral with said inner side wall of said annular groove at or above a midportion of said inner side wall and spaced from said outer side wall of said annular groove.

10. The self-attaching nut as defined inclaim 9, wherein said first plurality of circumferentially spaced ribs integral with said outer side wall of said annular groove extend beyond a midportion of said bottom wall, and said second plurality of circumferentially spaced ribs integral with said inner side wall extend beyond said midportion of said bottom wall, such that said first and second plurality of circumferentially spaced ribs overlap at said midportion of said bottom wall.

11. The self-attaching nut as defined inclaim 9, wherein said outer side wall of said annular groove further includes a plurality of circumferentially spaced generally radial notches.

12. The self-attaching nut as defined inclaim 11, wherein each of said generally radial notches includes an outer side wall extending generally perpendicular to said annular panel support face.

13. The self-attaching nut as defined inclaim 11, wherein each of said generally radial notches includes an outer wall and opposed generally parallel generally radial side walls extending from said outer wall of said generally radial notches to said outer wall of said annular groove.

14. The self-attaching nut as defined inclaim 11, wherein said first plurality of circumferentially spaced ribs are integral with an outer wall of said generally radial notches.

15. The self-attaching nut as defined inclaim 9, wherein said planar top face of said circumferentially spaced ribs is generally rectangular.

16. The self-attaching nut as defined inclaim 9, wherein said outer side wall of said annular groove is inclined toward said inner side wall.

17. The self-attaching nut as defined inclaim 16, wherein inner side wall of said annular groove is inclined toward said outer side wall of said annular groove.

18. A self-attaching nut for attachment to a panel, comprising:

a central projecting pilot portion, a panel support face on at least opposed sides of said pilot portion, and a groove in said panel support face adjacent said pilot portion having a bottom wall, an inner side wall adjacent said pilot portion inclined outwardly from said bottom wall and an outer side wall inclined inwardly toward said inner side wall, and a plurality of spaced ribs integral with and projecting from said bottom wall each having a planar top face inclined toward said bottom wall, including a first plurality of spaced ribs integral with said outer side wall extending toward said inner side wall beyond a midportion of said bottom wall of said groove and spaced from said inner side wall, and a second plurality of spaced ribs integral with said inner side wall extending toward said outer side wall beyond said midportion of said bottom wall and spaced from said outer side wall, such that said first and second plurality of spaced ribs overlap at said midportion of said bottom wall.

19. The self-attaching nut as defined inclaim 18, wherein said panel support face surrounds said central projecting pilot portion and said groove in said panel support face is annular and surrounds said pilot portion, and said first and second plurality of spaced ribs extending radially.

20. The self-attaching nut as defined inclaim 18, wherein each of said first plurality of spaced ribs is between two of said second plurality of spaced ribs.

21. The self-attaching nut as defined inclaim 18, wherein said top face of said ribs is generally rectangular.

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